X ray questions:What material is suitable in windows for hard X-rays?

In summary, for hard X-rays at 200 eV, the most suitable material for a reflective coating would be a free-standing SiN membrane on a Si frame. This is due to its low Z value and commercial availability. For X-rays above 3.5keV, Beryllium or CVD diamond can be used, while for hard X-rays above 20keV, Al, plastics, or Si wafers are suitable. However, for 200 eV, a naked Si mirror without any coating would be the best option due to its critical angle and high quality. The Center for X-Ray Optics offers resources for calculating the transmission and reflectivity of soft X-rays.
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runnerwei
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What material is suitable in windows for hard X-rays?

What material would you choose as reflective coating of X-rays mirrors for radiation at 200 eV? Why?
 
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Hmm, 200 eV is very very soft. The only window you can use for that is a free-stainding SiN membrane one a Si frame (substrate with a small window etched into it). These are commercially available, up to maybe a few window mm size.

A window is always a compromise of thickness and the material's absorption length. The latter depends on Z. Generally speaking you want Z as low as you can get, but the material has to withstand possible radiation damage.

For x-rays above 3.5keV or so you can use Beryllium (Z= 4 for large pieces) or CVD diamond (Z=6 for smaller pieces). For hard x-rays above 20keV or so you can use Al, plastics or even Si wafers.

For 200 eV I would use a naked Si mirror without any coating. The critical angle at 200 eV is large enough, and Si you can get in excellent quality.

Check out the Center for X-Ray Optics. There you can calculate transmission and reflectivity of softish X-rays.

http://henke.lbl.gov/optical_constants/
 

1. What are X-rays and how do they work?

X-rays are a form of electromagnetic radiation with a shorter wavelength than visible light. They can penetrate through many materials and are commonly used in medical imaging and scientific research. X-rays work by passing through an object and being absorbed differently depending on the density and composition of the material.

2. Why do X-rays require special windows?

X-rays are highly energetic and can easily pass through most materials, including glass. This means that ordinary windows would not be able to contain or block X-rays, making them unsuitable for use in areas where X-rays are present.

3. What materials are suitable for X-ray windows?

Materials that are suitable for X-ray windows must be able to block or attenuate X-rays while still allowing enough of them to pass through for imaging purposes. Common materials used for X-ray windows include lead, beryllium, and aluminum.

4. How thick should an X-ray window be?

The thickness of an X-ray window depends on the energy and intensity of the X-rays being used. Thicker windows are needed for higher energy X-rays, while thinner windows are suitable for lower energy X-rays. Generally, the thickness of an X-ray window should be at least half of the maximum X-ray energy being used.

5. Are there any safety precautions to take when working with X-rays and X-ray windows?

Yes, there are several safety precautions that should be taken when working with X-rays and X-ray windows. These include wearing appropriate protective gear, using shielding materials, and following proper handling and disposal procedures. It is important to always follow safety guidelines and regulations when working with X-rays to minimize the risk of exposure to harmful radiation.

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